An X-ray CT apparatus is an image diagnosis apparatus that radiates X-rays, detects X-rays transmitted through a subject, and reconstructs an image inside the subject from the projection data indicating the intensity of the detected X-rays.
This system radiates X-rays around the subject from multiple directions, performs scanning by 360°, for example, and obtains projection data. From this projection data, one tomographic view can be reconstructed. Moreover, it is possible to move the scanning position continuously in the direction of the subject's body axis and obtain a plurality of sets of projection data. Alternatively, if a so-called multi-row detector CT having a plurality of X-ray detectors is used, it is possible to obtain a plurality of sets of projection data simultaneously. Based on that plurality of sets of projection data, a volume image, which is a three-dimensional image, can be reconstructed.
Obtaining the projection data is performed with an X-ray detector that has an X-ray detecting element. Because detection sensitivity of the X-ray detecting element depends on temperature, it is desirable for the temperature of the X-ray detector to be maintained constant (for example, approximately 25±1° C.).
Therefore, it is common to install a warming means such as a heater in the X-ray detector to make temperature adjustments.